ABSTRACT The T-shaped deep mixing column (TDM) is a new proposed technique used to increase the ultimate load of the deep mixing column in loose sand. Enlarging the column diameter at a certain depth provides additional bearing area beneath the column under the enlarged part, which leads to an increase in the ultimate load. In this study, a series of laboratory tests were conducted to study and analyse the behaviour of stiffened deep cement mixing columns in loose sand under compression loading. The impact of different parameters such as stiffening methods, embedment ratio, TDM cap length ratio, TDM cap diameter ratio, and the position of the T-shape were studied. It is found that all stiffening methods significantly enhance the load-settlement response of the deep cement mixing (DCM) columns. The stiffening technique of reinforcement bars with a T-shape gives the greatest improvement, increasing the ultimate load by 191.1% compared with the conventional column.
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